Textbook by People's Education Press
Audio Link: https://www.10wanren.com/2/diandu/rjb7s/7s.html (Has copyright problems)
New edition of ebook(since 2012): http://www.haoduoyun.cc/book/rjb/yingyu/qinianji_2012s/20.shtml (Has copyright problems)
Alphabet: https://www.bilibili.com/video/BV1Ws411Q7rm?from=search&seid=7783663277630228083